**Contents**
[[!toc levels=3]]
# Miscellaneous operations
This chapter collects various topics, in sparse order
## Installing the boot manager
### fdisk
Sysinst, the NetBSD installation program, usually installs the NetBSD boot
manager on the hard disk. The boot manager can also be installed or reconfigured
at a later time, if needed, with the
[fdisk(8)](http://netbsd.gw.com/cgi-bin/man-cgi?fdisk+8+NetBSD-current)
command. For example:
# fdisk -B wd0
If NetBSD doesn't boot from the hard disk, you can boot it from the installation
floppy and start the kernel on the hard disk. Insert the installation disk and,
at the boot prompt, give the following command:
> boot wd0a:netbsd
This boots the kernel on the hard disk (use the correct device, for example sd0a
for a SCSI disk).
*Note*: Sometimes `fdisk -B` doesn't give the expected result (at least it
happened to me), probably if you install/remove other operating systems like
Windows 95 or Linux with LILO. In this case, try running `fdisk -i` (which is
known as `fdisk /mbr` from DOS) and then run again `fdisk` from NetBSD.
### installboot
There is another tool for installing a bootloader, named
[installboot(8)](http://netbsd.gw.com/cgi-bin/man-cgi?installboot+8+NetBSD-current).
Depending on the platform you are using, its usage differs, so you should read
the manpage and its extensive *EXAMPLES* section.
E.g., if you want to install the bootloader for a ffs filesystem to the
partition you have your NetBSD in (in this case, `sd0c`), you would use:
installboot -v /dev/rsd0c /usr/mdec/bootxx_ffs
## Deleting the disklabel
Though this is not an operation that you need to perform frequently, it can be
useful to know how to do it in case of need. Please be sure to know exactly what
you are doing before performing this kind of operation. For example:
# dd if=/dev/zero of=/dev/rwd0c bs=8k count=1
The previous command deletes the disklabel (not the MBR partition table). To
completely delete the disk, the whole device `rwd0d` must be used. For example:
# dd if=/dev/zero of=/dev/rwd0d bs=8k
The commands above will only work as expected on the i386 and amd64 ports of
NetBSD. On other ports, the whole device will end in c, not d (e.g. `rwd0c`).
## Speaker
I found this tip on a mailing list (I don't remember the author). To output a
sound from the speaker (for example at the end of a long script) the
[spkr(4)](http://netbsd.gw.com/cgi-bin/man-cgi?spkr+4+NetBSD-current)
driver can be used in the kernel config, which is mapped on `/dev/speaker`. For
example:
echo 'BPBPBPBPBP' > /dev/speaker
*Note*: The `spkr` device is not enabled in the generic kernel; a customized
kernel is needed.
## Forgot root password?
If you forget root's password, not all is lost and you can still recover the
system with the following steps: boot single user, mount `/` and change root's
password. In detail:
1. Boot single user: when the boot prompt appears and the five seconds
countdown starts, give the following command:
> boot -s
2. At the following prompt
Enter pathname of shell or RETURN for sh:
press Enter.
3. Write the following commands:
# fsck -y /
# mount -u /
# fsck -y /usr
# mount /usr
4. Change root's password:
# passwd root
Changing local password for root.
New password: (not echoed)
Retype new password: (not echoed)
#
5. Exit the shell to go to multiuser mode.
# exit
If you get the error `Password file is busy`, please see the section below.
## Password file is busy?
If you try to modify a password and you get the mysterious message `Password
file is busy, it probably means that the file `/etc/ptmp` has not been deleted
from the system. This file is a temporary copy of the `/etc/master.passwd` file;
check that you are not losing important information and then delete it:
# rm /etc/ptmp
*Note*: If the file `/etc/ptmp` exists you can also receive a warning message at
system startup. For example:
root: password file may be incorrect - /etc/ptmp exists
## Adding a new hard disk
This section describes how to add a new hard disk to an already working NetBSD
system. In the following example a new SCSI controller and a new hard disk,
connected to the controller, will be added. If you don't need to add a new
controller, skip the relevant part and go to the hard disk configuration. The
installation of an IDE hard disk is identical; only the device name will be
different (`wd#` instead of `sd#`).
As always, before buying new hardware, consult the hardware compatibility list
of NetBSD or ask on a mailing list to make sure the new device is supported by
NetBSD.
When the SCSI controller has been physically installed in the system and the new
hard disk has been connected, it's time to restart the computer and check that
the device is correctly detected, using the
[dmesg(8)](http://netbsd.gw.com/cgi-bin/man-cgi?dmesg+8+NetBSD-current)
command. This is the sample output for an NCR-875 controller:
ncr0 at pci0 dev 15 function 0: ncr 53c875 fast20 wide scsi
ncr0: interrupting at irq 10
ncr0: minsync=12, maxsync=137, maxoffs=16, 128 dwords burst, large dma fifo
ncr0: single-ended, open drain IRQ driver, using on-chip SRAM
ncr0: restart (scsi reset).
scsibus0 at ncr0: 16 targets, 8 luns per target
sd0(ncr0:2:0): 20.0 MB/s (50 ns, offset 15)
sd0: 2063MB, 8188 cyl, 3 head, 172 sec, 512 bytes/sect x 4226725 sectors
If the device doesn't appear in the output, check that it is supported by the
kernel that you are using; if necessary, compile a customized kernel (see
[[Compiling the kernel|guide/kernel]]).
Now the partitions can be created using the
[fdisk(8)](http://netbsd.gw.com/cgi-bin/man-cgi?fdisk+8+NetBSD-current)
command. First, check the current status of the disk:
# fdisk sd0
NetBSD disklabel disk geometry:
cylinders: 8188 heads: 3 sectors/track: 172 (516 sectors/cylinder)
BIOS disk geometry:
cylinders: 524 heads: 128 sectors/track: 63 (8064 sectors/cylinder)
Partition table:
0: sysid 6 (Primary 'big' DOS, 16-bit FAT (> 32MB))
start 63, size 4225473 (2063 MB), flag 0x0
beg: cylinder 0, head 1, sector 1
end: cylinder 523, head 127, sector 63
1: <UNUSED>
2: <UNUSED>
3: <UNUSED>
In this example the hard disk already contains a DOS partition, which will be
deleted and replaced with a native NetBSD partition. The command
`fdisk -u sd0` allows to modify interactively the partitions. The modified data
will be written on the disk only before exiting and fdisk will request a
confirmation before writing, so you can work relaxedly.
**Disk geometries**
The geometry of the disk reported by fdisk can appear confusing. Dmesg reports
4226725 sectors with 8188/3/172 for C/H/S, but 8188\*3\*172 gives 4225008 and
not 4226725. What happens is that most modern disks don't have a fixed geometry
and the number of sectors per track changes depending on the cylinder: the only
interesting parameter is the number of sectors. The disk reports the C/H/S
values but it's a fictitious geometry: the value 172 is the result of the total
number of sectors (4226725) divided by 8188 and then by 3.
To make things more confusing, the BIOS uses yet another *fake* geometry (C/H/S
524/128/63) which gives a total of 4225536, a value which is a better
approximation to the real one than 425008. To partition the disk we will use the
BIOS geometry, to maintain compatibility with other operating systems, although
we will lose some sectors (4226725 - 4225536 = 1189 sectors = 594 KB).
To create the BIOS partitions the command `fdisk -u` must be used; the result is
the following:
Partition table:
0: sysid 169 (NetBSD)
start 63, size 4225473 (2063 MB), flag 0x0
beg: cylinder 0, head 1, sector 1
end: cylinder 523, head 127, sector 63
1: <UNUSED>
2: <UNUSED>
3: <UNUSED>
Now it's time to create the disklabel for the NetBSD partition. The correct
steps to do this are:
# disklabel sd0 > tempfile
# vi tempfile
# disklabel -R -r sd0 tempfile
If you try to create the disklabel directly with
# disklabel -e sd0
you get the following message
disklabel: ioctl DIOCWDINFO: No disk label on disk;
use "disklabel -I" to install initial label
because the disklabel does not yet exist on the disk.
Now we create some disklabel partitions, editing the `tempfile` as already
explained. The result is:
# size offset fstype [fsize bsize cpg]
a: 2048004 63 4.2BSD 1024 8192 16 # (Cyl. 0*- 3969*)
c: 4226662 63 unused 0 0 # (Cyl. 0*- 8191*)
d: 4226725 0 unused 0 0 # (Cyl. 0 - 8191*)
e: 2178658 2048067 4.2BSD 1024 8192 16 # (Cyl. 3969*- 8191*)
*Note*: When the disklabel has been created it is possible to optimize it
studying the output of the command `newfs -N /dev/rsd0a`, which warns about
the existence of unallocated sectors at the end of a disklabel partition. The
values reported by newfs can be used to adjust the sizes of the partitions with
an iterative process.
The final operation is the creation of the file systems for the newly defined
partitions (`a:` and `e:`).
# newfs /dev/rsd0a
# newfs /dev/rsd0e
The disk is now ready for usage, and the two partitions can be mounted. For
example:
# mount /dev/sd0a /mnt
If this succeeds, you may want to put an entry for the partition into
`/etc/fstab`.
## How to rebuild the devices in /dev
First shutdown to single user, partitions still mounted `rw` (read-write); You
can do that by just typing `shutdown now` while you are in multi user mode, or
reboot with the `-s` option and make `/` and `/dev` read-writable by doing.
# mount -u /
# mount -u /dev
Then:
# mkdir /newdev
# cd /newdev
# cp /dev/MAKEDEV* .
# sh ./MAKEDEV all
# cd /
# mv dev olddev
# mv newdev dev
# rm -r olddev
Or if you fetched all the sources in `/usr/src`:
# mkdir /newdev
# cd /newdev
# cp /usr/src/etc/MAKEDEV.local .
# ( cd /usr/src/etc ; make MAKEDEV )
# cp /usr/src/etc/obj*/MAKEDEV .
# sh ./MAKEDEV all
# cd /
# mv dev olddev; mv newdev dev
# rm -r olddev
You can determine $arch by
# uname -m
or
# sysctl hw.machine_arch